HIVE-4599 : VectorGroupByOperator steals the non-vectorized children and crashes query if vectorization fails (Jitendra Nath Pandey via Ashutosh Chauhan)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/vectorization@1490837 13f79535-47bb-0310-9956-ffa450edef68